Cooling of heat engines



Jan. 5,1937, M. VULLIERME COOLING OF HEAT ENGINES .Filed March 16, 1952I lnewr: Marcel mater-M, /xfflzwzr Patented Jan. 5, 1937 UNITED STATESPATENT oFF cE Application March 16, 1932, Serial No. 599,296 In FranceMarch 20, 1931 4 Claims.

The present invention relates in general to means for cooling heatengines, such as internal combustion engines, and more particularly tomeans for cooling aircraft engines.

It has been hitherto the custom to cool engines by the use of radiators,or of apparatus in which a flat stream of liquid flows along a fixedwall such as the outer surface of the airplane body. In the first case,the weight of the conventional radiator and its resistance to forwardtravel are considerable, and in the second case the weight is stillgreater, as only one wall of the cooling device serves for theevacuation of the heat, while on the other hand the arrangement isfragile as well as bulky. It is a known fact that the resistance of theconventional exposed radiator-to forward travel is proportional to thesquare of the speed, while the transmission of the heat to thesurrounding air is only proportional to the speed itself. For thisreason, attempts have been made to produce an apparatus that would offerno resistance to travel, and in which the speed of the air in contactwith the cooling walls would be great. 7

The present invention consists in circulating the cooling fluid, such aswater, in a device adapted to rotate at high speed in the surroundingair, or other fluid. Thus for an airplane engine, the cooling fluid maybe circulated in the interior of the propeller. The propeller may beformed with apertures or recesses, reducing its weight. Theengine-cooling fluid, or main fluid, may be circulated in a suitablecooling device which is cooled by means of an auxiliary fluidcirculating in the recesses in the propeller.

The circulation of the fluid may be assured by the rotation of thepropeller itself, and thus the usual pump may be eliminated. In apreferred form of construction, the conduits for the supply and thedischarge of the fluid have their openings at different distances fromthe axis of the propeller hub, thus producing the difference of pressurerequired for the circulation of the liquid. The hub may be madeleakproof during the rotation, by the use of sheet metal plates servingto close the joint between the fixed and the movable part.

In one form of construction of the propeller blade, suitable holes orbores 'may be formed in order to contain the tubes in whlchthe coolingfluid is circulated. The bores are preferably formed in a metallicpropeller, before the blades are subjected to torsion, and each borewill preferably contain a partition by which it is divided into twoconduits serving respectively for the forward and for the returncirculation of the liquid.

In an effective arrangement, a stationary device may be mounted near thepropeller hub, through which device the water is circulated. This deviceis preferably provided with a circult for the main fluid of the engine,and with a second circuit for the auxiliary fluid circulating in theblades. The fluid circulating in the propeller contacts a portion of thestationary device forming the main fluid circuit. Thus the deviceprovides a heat exchange medium for the two fluids in the two circuits.

In the event of breakage of a tube, the cooling liquid will rapidlyescape. This can be prevented by means of valves which are closed by theliquid when the latter exceeds a given speed, and thus the valve willclose the inlet of the damaged tube.

The description is illustrated by the accom panyingdrawing which isgiven by way of example.

Figure 1 is a view in section taken through the central part of apropeller in a plane passing through the axis of rotation and throughthe axes of the blades.

Figure 2 is a view similar to Fig. 1 of a modified form of propeller andcooling system.

Referring more particularly to the drawing, there is shown in Figure 1 ashaft I carrying a propeller, of which only the hub 2 and the stubs ofthe blades 3 and 4 are shown. In the hub 2 are formed two annularrecesses 5 and B. The recess 5 is deeper than recess 6 so that the outerextremity l of the recess 5 is annularly farther removed from the shaftthan the outer extremity 8 of the recess 6, communicating with theserecesses are conduits 9 and II and i0 and I2 respectively, the conduitsbeing bored longitudinally of the blades. The conduits ll, l2 areconnected together at l3. near the end of the blade, and the conduits 9,l0 may be accordingly connected together in like manner.

The shaft I is surrounded by conduits formed by walls l4, l5, l6, whichare coaxial with the shaft and extend within the hub, then expanding toform four flaring walls l'l, I8, is, 20. At the outer extremity of theconduit formedby walls l1, i8 is thus formed an outlet 2| which isradially closer to the shaft 1 than the corresponding inlet 22 of theconduit formed by walls I9, 20. The passages provided by the conduitwalls l4, l5, and by the conduit walls l5, it, are respectivelyconnected with the water cooling system of the engine driving thepropeller, this When the propeller is in motion, the device thus formedacts as a pump for circulating the liquid in the direction of the arrows23, 24, 25, 26, 21 because the inlet conduit formed by walls [4 and i5and the outlet conduit formed by walls I5 and I6 are spaced atdifl'erent distances from the axis oi rotation of the propeller. Thisconstruction produces in eiiect a U-shaped column of water, the legs ofwhich are of unequal length, so that upon rotation of the propeller, andconsequent production of centrifugal force, the legs of the column tendto equalize in length and thereby produce a movement of the fluid fromthe inlet conduit to the outlet. When flowing through the interior ofeach blade, the liquid is cooled to a great degree, owing to the speedof the air in contact with the blades. Thus the heat produced by theengine and contained in the water entering at 23 is readily imparted tothe surrounding air by this device which offers practically no headresistance to the forward travel.

Figure 2 represents a propeller having two metallic blades 28, 29 whichmay be securedto the hub 30 in any suitable manner. The hub itself ismounted on a shaft 3|.- Before giving the necessary torsion to theblades 28, 29, these latter are pierced with longitudinal conduits 32,33, 34,

35, into each of which is fitted a tube 36, divided into two conduits bya middle partition 31, which conduits are in communication at the end ofthe blade at 48. After the blade has been thus arranged, it is given theusual torsion in order to produce the desired pitch.

The blade is provided near its inner end with a ring 38 which serves forcommon circulation. The ring comprises two annular grooves 39, 40; theouter groove 39 is connected by channels 4| with the conduits 42, 43;the inner groove 40 is connected by another set of channels 44 with theconduits 45, 45.

A ring-shaped member 41 is secured to the rear side of the propeller,and in it are formed two annular recesses 49, 50, analogous to therecesses 5, 6 of Figure 1. The recess 49 is connected by a channel 5|with the groove 39 of the blade 28 and with the corresponding groove 52of the blade 29; in like manner, the recess 50 is connected with thegrooves 40 and 53.

The recesses 49, 50 contain a stationary member adapted for a coolingaction between the water from the engine, or the main cooling fluid, andthe liquid circulating in the blades, or the auxiliary fluid.

For this purpose, the apparatus comprises three pairs of sheet metalpieces such as 54, 55 and 56, 51, forming a torus-shaped device whichhas the form of a J in cross section, as observed in the figure. Themain fluid enters through the pipe 58 and proceeds between the sheetmetal pieces oi! the three pairs, thus circulating in the torus andreturning to the engine through the pipe 59.

On the other hand, due to the rotation of the propeller, and in the sameconditions as described in connection with Figure 1, the auxiliary fluidflows in the direction of the arrows 60, 6|, thus flowing between thethree pairs of closely-spaced 2,068,661 being readily eflected, as thewalls l4, I5, I, and

sheet metal pieces, whereby one fluid is cooled by the other.

The apparatus is made leakprooi by means of an annular packing member 32consisting 01' an elastic substance which is secured to the sheet metalpiece 54 to irictionally engage a sheet metal ring 63.

To provide for the case oi! damage causing a considerable leakage, forinstance in the conduit 46, there may be provided suitable check valvessuch as shown at 64 to automatically close the conduit. The valve may bemounted at the end of a spring strip 65, and when the rate 0! flow ofthe liquid increases, the valve will be applied against the outlet ofthe conduit.

Having now particularly described and ascertained the nature of myinvention and in what manner the same is to be performed, I declare thatwhat I claim is:

1. For use in a vehicle a heat engine cooled by a main fluid, thecombination of a motive propeller driven by' said engine, means forcirculating said main fluid to act as a cooling medium and means forcirculating a supplementary fluid in the interior of said propeller forcooling said main fluid.

2. For use in a vehicle a heat engine cooled by a main fluid, thecombination of a motive propeller driven by said engine, means forcirculating said main fluid to act as a cooling medium and means forcirculating a supplementary fluid in the interior of said propeller forcooling said main fluid, said propeller having a hub, a heat exchangingdevice located in said hub, said heat exchanging device having conduitsthrough which the fluid circulating in the propeller passes, said heatexchanging device also having conduits for the cooling of the fluidcirculating in said engine.

3. In a vehicle operated by an internal combustion engine necessitatingheat disssipation by a circulating fluid, a drive shaft to which thepower developed by said engine is transmitted, a propeller of theaeroplane type attached to and rotated by said shaft and. constitutingmeans for propelling the vehicle, a liquid circulating system forcooling the engine including radially disposed conduits in thepropeller, and concentric annular inlet and outlet conduits surroundingthe shaft and in communication with the radial conduits in thepropeller, whereby the heat of the combustion engine may be dissipatedby the liquid circulating within the propeller.

4. In a vehicle operated by an internal combustion engine necessitatingheat dissipation by a fluid circulating through a water jacket in theengine, a drive shaft to which the power developed by the engine istransmitted, a propeller of the aeroplane type attached to and rotatedby said shaft and constituting the means for propelling the vehicle, anda liquid circulation system for cooling the engine including radiallydisposed conduits in the propeller and concentric annular inlet andoutlet conduits surrounding the shaft communicating with the radialconduits and the water jacket whereby liquid may be circulated throughthe water jacket and the propeller to cool the engine.

MARCEL VULLIERME.

